Camshaft Position Sensor: Description and Operation

Fig. 3 Camshaft Position Sensor:

PURPOSE
The PCM determines fuel injection synchronization and cylinder identification from inputs provided by the camshaft position sensor and crankshaft position sensor. From the two inputs, the PCM determines crankshaft position.

The sensor also acts as a thrust plate to control camshaft end play.

Fig. 4 Target Magnet--Typical:

Fig. 5 Target Magnet Polarity:

OPERATION
The camshaft position sensor attaches to the rear of the cylinder head Fig. 4. A target magnet attaches to the rear of the camshaft and indexes to the correct position. The target magnet has four different poles arranged in an asymmetrical pattern. As the target magnet rotates, the camshaft position sensor senses the change in polarity Fig. 5. The sensor input switches from high (5 volts) to low (0.30 volts) as the target magnet rotates. When the north pole of the target magnet passes under the sensor, the output switches high. The sensor output switches low when the south pole of the target magnet passes underneath.

The camshaft position sensor is mounted to the rear of the cylinder head.